This shared instrumentation proposal seeks funding for the purchase of an AB Sciex next generation TripleTOF 5600 quadrupole orthogonal time-of-flight mass spectrometer. This mass spectrometer will be part of an integrated nano-2DLC MS/MS system to be completed through independent funds already committed by the Buck Institute for this purpose. In brief, we propose to operate this integrated TripleTOF mass spectrometry system exclusively for the on-line separation and analysis of complex peptide and protein mixtures as part of large group of 12 independent principal investigators from the Buck Institute and 6 external investigators that represent a total of seven institutions or universities. Together, these researches bring together 21 NIH funded grants, all of which have significant needs for state-of-the-art mass spectrometry for various proteomics applications that require the highest sampling efficiency, resolution and sensitivity. The most critical features of this new instrumentation will be to the high resolution capabilities of data acquisition in both MS1 (40,000) and MS2 (15,000 - 35,000), the number of tandem mass spectra that can be acquired in a given time (typically 35 scans /sec), the exquisite sensitivity (low attomoles) and high dynamic range. These operating parameters will also allow several unique data acquisition scans, including SWATH and pseudo-MRM, and novel quantitation approaches that uses both MS1 and MS2 ion intensity data. The unique capabilities of this instrumentation will be directed at a diverse array of protein and proteomic application where mass spectrometry is used for identification, discovery, and global quantitation in very complex biological samples. The identification and quantitation of biologically important enzymatic and non-enzymatic posttranslational modifications will be a critical use of this new mass spectrometer, including protein phosphorylation, lysine-acetylation, and oxidative damage, among others. Overall, the acquisition of this instrument to the Chemistry & Mass Spectrometry Core at the Buck Institute for Research on Aging will greatly improve the throughput, experimental design, and discovery rate of over 19 projects that are examining key issues of human health and health span, including the biology of aging, neurodegenerative disease, diabetes, cancer, disease biomarker discovery, and infectious diseases.